Many packaging arrangements for opto-electronic assemblies utilize an interposer member (i.e. “carrier”) as a support structure, particularly in the three-dimensional (and 2.5-dimensional) packaging architectures that are currently being developed to meet the requirements of high I/O pin-out integrated circuits and their high density routing to an associated package or board. In most cases, the interposer member comprises silicon, although glass-based interposers are used at times.
While the use of an interposer is considered to be a preferred packaging structure for allowing the integration of high speed, low power optical interfaces with necessary electronic components, the amount of heat that can be generated during the operation of the components can be problematic. Thermal management issues are of a significant concern when it is desired to integrate an optical source (e.g., laser or LED) with the other opto-electronic components, since the temperature of the area surrounding the optical source impacts the operational stability of the optical device. Various other opto-electronic components are also sensitive to changes in ambient temperature and, in particular, suffer from poor performance at elevated temperatures.
Temperature-related problems in opto-electronic packaging have been addressed in the past in a variety of different forms. For example, U.S. Pat. No. 6,252,726 issued to J-M Verdiell on Jun. 26, 2001, describes an opto-electronic package arrangement where the optical components are housed within a first package enclosure and the electrical components are housed within a second, separate package enclosure located either above or below the first package enclosure. A separate heat sink (e.g. a Peltier effect device) is attached to the arrangement and use to draw heat away from the optical components.
U.S. Pat. No. 6,762,938 issued to P. Tayebati et al. on Jul. 13, 2004 describes an arrangement for controlling the temperature of an opto-electronic package by using at least two separate thermal control systems, with one system directly controlling the operational temperature of a temperature-sensitive optical device and a second, auxiliary system controlling the temperature of the complete package.
These prior art techniques may perform well in some circumstances, but as the level of integration of optical and electrical components continues to increase, and competes with the desire to reduce the overall size of the complete opto-electronic package, the inclusion of additional temperature control systems and/or the use of separate packaging structures is not desirable. Another approach described in U.S. Pat. No. 7,327,022 issued to G. S. Claydon et al. on Feb. 5, 2008 describes a more integrated arrangement, based upon a platform technology for optical and electrical interconnections. In this arrangement, the optical components are formed on a rigid substrate and the electronics are disposed on a thermal substrate, with a gap between the two substrates used to provide thermal isolation. The thermal substrate itself functions as a heat exchanger to dissipate the heat energy created by the electronics. This arrangement still relies on the use of separate thermal paths (in this case, micropipes) for use in removing heat from the temperature-sensitive optical components.
Various other integrated structures that utilize some type of interposer in an opto-electronic arrangement create specific cavities in the interposer where heat sink devices may be located and use to dissipate the generated thermal energy. See, for example, US Patent Application Publication 2011/021044 dated Sep. 1, 2011 and US Patent Application Publication 2012/0106117 for examples of this type of arrangement.
While all of these configurations, to a greater or lesser degree, address thermal management issues in an opto-electronic assembly, the need for additional space and/or separate substrates for optics and electronics to address temperature-related issues remains a concern.